Add support for configuring network interface/IP binding

[bryanchriswhite]

Description

Currently, PinShare binds to 0.0.0.0 (all interfaces) for the API server and uses localhost for internal health checks. This should be configurable to allow users to:

• Bind to specific network interfaces
• Choose between IPv4 and IPv6
• Restrict API access to specific IPs

Affected Components

• internal/api/main_api.go - API server binding
• cmd/pinsharesvc/process.go - IPFS configuration (Addresses.API, Addresses.Gateway)
• internal/app/app.go - Health check dial addresses

Proposed Solution

Add configuration options for:

• api_bind_address - Address for API server to bind to (default: 0.0.0.0)
• ipfs_bind_address - Address for IPFS to bind to (default: 127.0.0.1 for API/Gateway, 0.0.0.0 for Swarm)

References

This issue was identified during PR #3 code review.